Worth Watching: ‘Agatha Raisin’ Halloween Mystery, ‘Deuce’ Series Finale, ‘Prodigal Son’

A selective critical checklist of notable Monday TV:

Agatha Raisin and the Haunted House (streaming on Acorn TV): The delightful snoop played with a wink and a grin by Ugly Betty‘s Ashley Jensen is back — or as her new client puts it, “You’re that ghastly amateur sleuth with a disgustingly low neckline and even lower morals.” Well, no one’s perfect, least of all Agatha. But in a new Halloween-themed movie special of campy catnip, Agatha is now the proud owner of a spanking-new P.I.’s license and her own detective agency. She even has a Scooby Gang of sorts including loyal boyfriend James (Jamie Glover), sidekick Roy (Mathew Horne), bestie Sarah (Lucy Liemann), admiring constable Bill Wong (Matt McCooey) and a klutzy new assistant, Toni (Jodie Nyack), with impressive powers of recall. Agatha’s first official case involves an unlikable battle-ax who believes, “Someone’s trying to scare me to death, quite literally” as shrieks in the night besiege anyone who dares stay in Ivy Hall. When her client expires, the whole village — including medieval battle re-enactors — become suspects, because no one liked horrible old Olivia Witherspoon (Richenda Carey). Agatha’s on the case, but she needs company. As she puts it during a dark night of slapstick terror: “I’m not going anywhere on my own. Have you never seen Scooby Doo?”

The Deuce (9/8c, HBO): Change is coming to the seedy Times Square neighborhood as the evocative series about the bygone days of New York’s sex industry comes to a close, with Midtown in the throes of redevelopment and nearly everyone making choices about their future. That includes Candy (Maggie Gyllenhaal), who went from street prostitute to feminist skin-flick auteur, and Vincent (James Franco), who’s still trying to extricate himself from the mob.

Prodigal Son (9/8c, Fox): More twists in this psychological thriller, one of the fall’s best new series, as troubled Malcolm (Tom Payne) chases clues found in a childhood photo that shows him and Martin (Michael Sheen), his serial-killer father, on a camping trip lost to memory. “Those who can’t remember their past are condemned,” Malcolm quips, though he’s dead serious about his ability to distinguish reality from visions. Malcolm’s latest head trip is triggered by a case in which he identifies perhaps too closely with the young son (Clark Furlong) of a murder victim. Adding to his trauma: news from sister Ainsley (Halston Sage) that she plans to interview the father she never knew, but whom Malcolm and mother Jessica (Bellamy Young) know all too well. Ainsley’s first encounter with Martin is, putting it mildly, creepy.

Inside Monday TV: Smithsonian Channel delves into recent British royal history in Princess Diana’s “Wicked” Stepmother (8/7c), exploring the fraught relationship of Diana Spencer with her stepmother, Raine — whom a teenage Di once dubbed “Acid Raine” — and their reconciliation in the early ’90s after Princess Diana left Charles and lost her dad… What’s really spooky about the Halloween edition of ABC’s Dancing with the Stars (8/7c)? Not the promised “epic zombie number,” or the group dances divided between “Team Trick” and “Team Treat,” but the fact that Sean Spicer is still around, tripping the light not-so-fantastic… PBS’s Independent Lens takes a provocative look inside the practice of surrogacy in “Made in Boise” (10/9c, check local listings at pbs.org). The documentary focuses on four women who are part of a boom in Idaho’s state capital, where there are no laws governing surrogacy and it is estimated that one in 15 mothers will eventually carry a baby for a stranger.